Reliability and Functionality of Repairable Systems Using a Minimal Set of Metrics: Design and Maintenance of a Smart Charging Microgrid

Author(s):  
Vijitashwa Pandey ◽  
Annette G. Skowronska ◽  
Zissimos P. Mourelatos ◽  
David Gorsich ◽  
Matthew Castanier

The definition of reliability may not be readily applicable for repairable systems. Our recent work has shown that multiple metrics are needed to fully account for the performance of a repairable system under uncertainty. Optimal tradeoffs among a minimal set of metrics can be used in the design and maintenance of these systems. A minimal set of metrics provides the most information about the system with the smallest number of metrics using a set of desirable properties. Critical installations such as a remote microgrid powering a military installation require a careful consideration of cost and repair strategies. This is because of logistical challenges in performing repairs and supplying necessary spare parts, particularly in unsafe locations. This paper shows how a minimal set of metrics enhances decision making in such a scenario. It enables optimal tradeoffs between critical attributes in decision making, while guaranteeing that all important performance measures are satisfied. As a result, cost targets and inventory planning can be achieved in an optimal way. We demonstrate the value of the proposed approach using a US Army smart-charging microgrid installation.

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Annette G. Skowronska ◽  
David J. Gorsich ◽  
Vijitashwa Pandey ◽  
Zissimos P. Mourelatos

Vehicles connected to electric systems are considered “plug-in” vehicles. They can be an integral part of a microgrid. Ground vehicles have become more electrified over time, providing electrical power for the propulsion system (hybrid) and a complex suite of auxiliary power systems, enhancing their use in microgrids. Optimizing the microgrid system for performance and reliability considering many external loads and sources is a challenging problem. This is especially true when the plug-in vehicles may enter and leave the microgrid randomly becoming either sources or loads. The microgrid is a repairable system. Recent work has shown that multiple metrics are needed to fully account for the performance of repairable systems under uncertainty. In this paper, we propose a decision-based framework to design and maintain repairable systems for optimal performance and reliability using a set of metrics such as minimum failure free period (MFFP), number of failures in planning horizon, and cost. Optimal tradeoffs among a minimal set of metrics (MSOM) can be used in the design and maintenance of these systems. The optimal solution includes the initial design, the system maintenance throughout the planning horizon, and the protocol to operate the system. Critical remote military installations with plug-in vehicles connected to the microgrids require careful consideration of cost and repair strategies because of logistical challenges in performing repairs and supplying necessary spare parts in unsafe locations. We show how a MSOM helps to solve the complex optimization problem of finding the best microgrid power management strategy considering performance, reliability, and cost.


Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 6120
Author(s):  
Nikolaos Milas ◽  
Dimitris Mourtzis ◽  
Emmanuel Tatakis

During the last decade, the technologies related to electric vehicles (EVs) have captured both scientific and industrial interest. Specifically, the subject of the smart charging of EVs has gained significant attention, as it facilitates the managed charging of EVs to reduce disturbances to the power grid. Despite the presence of an extended literature on the topic, the implementation of a framework that allows flexibility in the definition of the decision-making objectives, along with user-defined criteria is still a challenge. Towards addressing this challenge, a framework for the smart charging of EVs is presented in this paper. The framework consists of a heuristic algorithm that facilitates the charge scheduling within a charging station (CS), and the analytic hierarchy process (AHP) to support the driver of the EV selecting the most appropriate charging station based on their needs of transportation and personal preferences. The communications are facilitated by the Open Platform Communications–Unified Architecture (OPC–UA) standard. For the selection of the scheduling algorithm, the genetic algorithm and particle swarm optimisation have been evaluated, where the latter had better performance. The performance of the charge scheduling is evaluated, in various charging tasks, compared to the exhaustive search for small problems.


2018 ◽  
Author(s):  
Camilla Kao ◽  
Russell Furr

Conveying safety information to researchers is challenging. A list of rules and best practices often is not remembered thoroughly even by individuals who want to remember everything. Researchers in science thinking according to principles: mathematical, physical, and chemical laws; biological paradigms. They use frameworks and logic, rather than memorization, to achieve the bulk of their work. Can safety be taught to researchers in a manner that matches with how they are trained to think? Is there a principle more defined than "Think safety!" that can help researchers make good decisions in situations that are complex, new, and demanding?<div><br></div><div>Effective trainings in other professions can arise from the use of a mission statement that participants internalize as a mental framework or model for future decision-making. We propose that mission statements incorporating the concept of <b>reducing uncertainty</b> could provide such a framework for learning safety. This essay briefly explains the definition of <b>uncertainty</b> in the context of health and safety, discusses the need for an individual to <b>personalize</b> a mission statement in order to internalize it, and connects the idea of <b>greater control</b> over a situation with less uncertainty with respect to safety. The principle of reducing uncertainty might also help <b>non-researchers</b> think about safety. People from all walks of life should be able to understand that more control over their situations provides more protection for them, their colleagues, and the environment.</div>


Author(s):  
Francesco Maria Romano ◽  
Guido Sciaudone ◽  
Silvestro Canonico ◽  
Francesco Selvaggi ◽  
Gianluca Pellino

: Hemorrhoidal Disease (HD) is widely diffused throughout the general population. The system of classification currently used to categorize this pathology is that of Goligher (1975). This system only defines the morphology of the most represented hemorrhoid bearing. Several attempts in literature have been made to replace this system, but as of yet, no single system has been universally accepted. Some studies, however, have succeeded in identifying specific characteristics, besides morphology, that would be able to aptly define HD. An analysis of this literature, with careful consideration of the scores that have previously been proposed, is necessary in order to deepen and stimulate discussion about a possible new definition of HD.


2000 ◽  
Vol 14 (3) ◽  
pp. 325-341 ◽  
Author(s):  
Heather M. Hermanson

The purpose of this study is to analyze the demand for reporting on internal control. Nine financial statement user groups were identified and surveyed to determine whether they agree that: (1) management reports on internal control (MRIC) are useful, (2) MRICs influence decisions, and (3) financial reporting is improved by adding MRICs. In addition, the paper examined whether responses varied based on: (1) the definition of internal control used (manipulated as broad, operational definition vs. narrow, financial-reporting definition) and (2) user group. The results indicate that financial statement users agree that internal controls are important. Respondents agreed that voluntary MRICs improved controls and provided additional information for decision making. Respondents also agreed that mandatory MRICs improved controls, but did not agree about their value for decision making. Using a broad definition of controls, respondents strongly agreed that MRICs improved controls and provided a better indicator of a company's long-term viability. Executive respondents were less likely to agree about the value of MRICs than individual investors and internal auditors.


Mathematics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1389
Author(s):  
Julia García Cabello ◽  
Pedro A. Castillo ◽  
Maria-del-Carmen Aguilar-Luzon ◽  
Francisco Chiclana ◽  
Enrique Herrera-Viedma

Standard methodologies for redesigning physical networks rely on Geographic Information Systems (GIS), which strongly depend on local demographic specifications. The absence of a universal definition of demography makes its use for cross-border purposes much more difficult. This paper presents a Decision Making Model (DMM) for redesigning networks that works without geographical constraints. There are multiple advantages of this approach: on one hand, it can be used in any country of the world; on the other hand, the absence of geographical constraints widens the application scope of our approach, meaning that it can be successfully implemented either in physical (ATM networks) or non-physical networks such as in group decision making, social networks, e-commerce, e-governance and all fields in which user groups make decisions collectively. Case studies involving both types of situations are conducted in order to illustrate the methodology. The model has been designed under a data reduction strategy in order to improve application performance.


2021 ◽  
Vol 24 (1_part_3) ◽  
pp. 2156759X2110119
Author(s):  
Brett Zyromski ◽  
Catherine Griffith ◽  
Jihyeon Choi

Since at least the 1930s, school counselors have used data to inform school counseling programming. However, the evolving complexity of school counselors’ identity calls for an updated understanding of the use of data. We offer an expanded definition of data-based decision making that reflects the purpose of using data in educational settings and an appreciation of the complexity of the school counselor identity. We discuss implications for applying the data-based decision-making process using a multifaceted school counselor identity lens to support students’ success.


2021 ◽  
Vol 13 (4) ◽  
pp. 2332
Author(s):  
Lena Bjørlo ◽  
Øystein Moen ◽  
Mark Pasquine

Artificial intelligence (AI)-based decision aids are increasingly employed by businesses to assist consumers’ decision-making. Personalized content based on consumers’ data brings benefits for both consumers and businesses, i.e., with regards to more relevant content. However, this practice simultaneously enables increased possibilities for exerting hidden interference and manipulation on consumers, reducing consumer autonomy. We argue that due to this, consumer autonomy represents a resource at the risk of depletion and requiring protection, due to its fundamental significance for a democratic society. By balancing advantages and disadvantages of increased influence by AI, this paper addresses an important research gap and explores the essential challenges related to the use of AI for consumers’ decision-making and autonomy, grounded in extant literature. We offer a constructive, rather than optimistic or pessimistic, outlook on AI. Hereunder, we present propositions suggesting how these problems may be alleviated, and how consumer autonomy may be protected. These propositions constitute the fundament for a framework regarding the development of sustainable AI, in the context of online decision-making. We argue that notions of transparency, complementarity, and privacy regulation are vital for increasing consumer autonomy and promoting sustainable AI. Lastly, the paper offers a definition of sustainable AI within the contextual boundaries of online decision-making. Altogether, we position this paper as a contribution to the discussion of development towards a more socially sustainable and ethical use of AI.


2007 ◽  
Vol 41 (6) ◽  
pp. 1065-1068 ◽  
Author(s):  
Timothy E Welty

Generic substitution of antiepileptic drugs is an issue that is gathering a lot of attention in the neurology community but is not receiving much attention within pharmacy. Several proposals have been drafted that restrict a pharmacist's decision-making in generic substitution. These proposals highlight concerns about the pharmacy community related to generic substitution. Careful consideration needs to be given to these issues by pharmacists and pharmacy professional organizations. Unless pharmacy as a profession takes strong positions in support of a pharmacist's ability to make decisions about pharmacotherapy and addresses many of the pharmacy-related problems of generic substitution, policies that negatively impact pharmacy will be established.


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